1. Field of the Invention
This invention relates to inhalers, particularly to an inhaler used for inhaling pharmaceutical powdered preparations so as to enable such preparations to reach a trachea, bronchi and pulmonary cells.
2. Related Art Statement
In general, in order to distribute pharmaceutical preparations into an oral cavity of the human body to reach the trachea, bronchi and pulmonary cells of a human body, there has been known use of an atomizing type spraying device. However, with the device of this type, patients tend to close the deep portion of the oral cavity instinctively or in a conditioned response at the moment of spraying, so that it has been difficult to accomplish the desired objective.
Therefore, to obviate the above-described disadvantage, there have been proposed inhalers for smoothly inhaling the pharmaceutical powdered preparations into the trachea, bronchi and pulmonary cells to accompany the inspiration of air by a patient.
As one of these inhalers, disclosed in Japanese Patent Laid-Open No. 53-136392, comprises: a straight-lined hollow barrel body formed with a chamber and provided at a side surface thereof with air intake openings that communicate with the chamber; and a lid sleeve connected to one end of this barrel body, having a capsule holding sleeve and being rotatable relative to the barrel body. When the barrel body and the lid sleeve are rotated relative to each other, a capsule insertion portion held by the capsule holding sleeve is engaged with an abutting portion in the barrel body, whereby the capsule is divided into a capsule barrel and a capsule head. The powdered preparations contained in the capsule are dropped into the chamber and inhaled into an oral cavity of the patient through a nozzle.
Furthermore, in a magazine "The Practitioner" March, 1982 issue, 226th volume, pages 565-567, there is disclosed an inhaler comprising: a straight-lined hollow inner barrel; and an outer barrel connected to one end of the inner barrel and rotatable relative to the inner barrel. The outer barrel is provided at one end with a capsule insertion hole and air intake openings. When the inner barrel is rotated relative to the outer barrel, a capsule insertion portion is engaged with an abutting portion in the inner barrel, so that a capsule is divided into a main body and a head and powdered preparations which fall into the inner barrel are inhaled from the other end of the inner barrel.
However, it has become apparent from studies made by the inventors of the present invention that the above-described two inventions of the prior art present serious problems when used as the inhaler.
First, the former, i.e. the invention of the prior art disclosed in the Japanese Patent Laid-Open No. 53-136392 presents the following problems.
(1) The inhaler as a whole is of a straight-line form. When the capsule is divided into a main body and the head thereof by the rotation of the hollow barrel body and the lid sleeve relative to each other, the powdered preparations which have fallen into the hollow barrel body may leak out of the hollow barrel body to the outside. Because of this, shortage or waste of the contained material may result. This problem is particularly notable because the capsule insertion hole is positioned at a location very close to the nozzle for inhaling.
(2) The air flow-in openings for the hollow barrel body are formed in the side surface, and the end face is blocked. Thus ideal turbulent flows are difficult to obtain in the chamber and the operating maneuvers of the capsule barrel which has fallen into the chamber are not briskly performed. Accordingly, the powdered preparations in the capsule barrel are difficult to discharge into the hollow barrel body, and further, the powdered preparations which have fallen into the chamber cannot be efficiently inhaled out of the chamber. Thus the powdered preparations remain in the capsule, and moreover, in the chamber. Therefore, an expected remedial result cannot be achieved due to the shortage of the planned dosage.
(3) Since the capsule holding sleeve is provided at a position very close to the inhaling nozzle, the capsule disturbs the patient when inhaling nozzle is put in his mouth to perform inhalation.
(4) Since the general form of the inhaler is of a straight-line cylindrical form, there is a possibility that the inhaler will roll off a flat surface such as a table.
Possibly due to the above-described serious disadvantages, the inhaler of the type described has not heretofore been put on the market as a product.
Next, the latter invention of the prior art presents the following serious drawbacks.
(a) The inhaler as a whole is of a straight-line form and the powdered preparations, which fall from the capsule into the inner barrel by the rotation of the inner barrel and the outer barrel relative to each other, leak out of the inner barrel to the outside as in the case of the previously described prior art
(1) As the result, an insufficient or wasteful dosage of the powdered preparations is caused.
(b) The air flow-in openings for the inhaler are formed in the end face of the outer barrel. However, the inhaler as a whole is of a straight-lined form, whereby ideal turbulent flows are difficult to develop in the inhaler during inhaling. Furthermore the operating maneuvers of the capsule barrel, which has fallen into the inhaler, are not briskly performed. Accordingly, the powdered preparations in the capsule barrel are not smoothly discharged. Moreover, the powdered preparations are not smoothly inhaled through the inhaling nozzle and remain in the inhaler. Furthermore, in this latter invention there is no disclosure of the size, shape or position of the air intake openings.
(c) In connection with Item (b), ideal turbulent flows are difficult to develop in the inhaler. Also the operating maneuvers of the capsule barrel which falls into the inhaler are not easily performed, and the powdered preparations in the capsule barrel are difficult to transfer out of the capsule barrel and thus remain therein. Because of these problems, an insufficient remedial result is obtained due to a shortage of the planned dosage.
(d) Furthermore, it has been determined from experiments made by the inventors of the present invention that the capsule head still held in the capsule insertion hole of the outer barrel after the capsule barrel is separated therefrom is open at the opening end thereof to the inhaler. Thus, to everyone's surprise, the powdered preparations in the inhaler are recirculated and received again in the capsule head by air streams generated in the inhaler and remain in the capsule head.
(e) Since the general form of the inhaler is of a straight-line cylindrical form, there is a possibility of that the inhaler will roll off a flat surface such as a table.